Nonlivering coating compositions



. ever, that in the case of enamels or pigmented than two months. 20 lacquers, these materials could not safely be used The coating materials in which malic acid may in combination with basic pigments because of a be used as the stabilizing agent may be any of pronounced tendency to gell or liver. the usual types of lacquers or varnish base enam- 45 directed toward modifying the resins. Up to the basic pigments with other materials such as tita- 45 Patented Sept. 7, 193 v I UNITED STATES PATENT CFFICE' 2,092,300 NoNLIvFlnmc COATING COMPOSITIONS Charles Begin, Terre Haute, 1nd,, 'assignor to Commercial Solvents Corporation, Terre Haute, Ind., a corporation of Maryland No Drawing Application October 19, 1934,

Serial No. 749,073

6 Claims. (01. 134-25) My invention relates'to improvements in coatculty by neutralizing the acidity of the resins ing compositions containing basic pigments and have also met with failure. modified polybaslc acid-polyhydric alcohol resins. I have now discovered that the addition of More specifically, my invention relates to im- .very small quantities of malic acid to the coatproved coating compositions of this nature having materials will reduce the tendency to liver 5 ing an increased resistance to gelling or livering. to a marked extent and, in some cases, will ob- A relatively large number of modified polybasic viate this difficulty entirely. In some instances acid-polyhydric alcohol resins have been dethe incorporation of only 0.25% of malic acid veloped for use in coating materials. These reswill' entirely prevent livering or agglomeration 1'0 ins, whieh are usually of the glycerol-phthalic of the coating material. In general, an addition 0 anhydride type, have been modified by the introof 0.25 to 2.0% of malic acid will prevent gelling duction of drying oils, non-drying or semi-drying for the ordinary shelf life of the coating maoils, phenol-aldehyde resins, and the like, to imterials. For example, in laboratory tests using prove their solubility in organic solvents and, in various lacquers and enamels containing zinc oxsame cases, to impart drying or oxidizing properide, those in which 0.5% of malic acid was in- 15 ties to them. All'of these resins have found use corporated had not livered at the end of a six as the basicfilm forrnirig ingredient of varnishes months observation period, whereas those con- 01 enamels or as a supplementary film-forming taining no malic acid had livered or agglomerated ingredient in lacquers; Ithasbeen found, how in. a substantially shorter time, usually in less i The liveringofjcoating materials of this type els. The lacquers may be prepared from nitromay take the form of-either gellation of the encellulose of the half-second type or other suit- 25 tire coating material or agglomeration of apart 'ably low viscosity cottons such as four second of the,material into large particles, leaving the cotton. The usual plasticizers such as dibutyl remainder as a liquid. The former-is the more phthalate, tricresyl phosphate or castor oil may common form of this phenomenon, but even inv be used. The solvents may be any of the usual this case agglomerates may-be found in the gelled esters, alcohols, ketones, ethers, etc., but as will 30 material. In the case of coating materials conbe pointed out below, a large proportion of hytaining relatively large amounts of zinc oxide and droxy acid esters such as butyl lactate should certain resins having a pronounced livering tendpreferably not be employed if the pigment comency, the gellation may take place within a few prises mainly basic pigments such as zinc oxide.

days after the preparation of the coating ma-. The enamels may be any of the usual types 35 terial and nearly always within a month. Cerprepared from modified polybasic acid-polyhytain factors, such as the acidity of the solvent dric alcohol resiris. The usual hydrocarbon solemployed, the amount of basic pigment utilized, vents may be used; and, with certain resins, drythe temperature, etc., will determine the speed ing oils and driers which are compatible with at which livering takes place, butin any event the resins and solvents may also be employed in 40 it will be found to occur if these two constituents the known manner. I

are present. In the case of either the lacquers or the enam- Numerous efforts have been made to counterels, the pigment may comprise essentially a. basic act this tendency to liver, particularly eflorts pigment such as zinc oxide or mixtures of such present time, however, none of these attempts nium dioxide, zinc sulphide, antimony oxide, and has met with success. If the nature of the resin the like.

is changed so as to avoid'livering, the desirable The malic acid may be incorporated into the film-forming properties are also modified to an coating materials in any convenient manner.

- unwanted extent. Attempts to avoid this difil- For example, it may be added prior to the intro- 50 duction of the pigment and thoroughly dispersed by grinding or agitation, or it may be ground into theliquid simultaneously with the pigment.

The following examples will serve to further illustrate my invention. Examples I and II represent simple formulae for a lacquer and an enamel, respectively, which illustrate the general application of my invention.

The above lacquer was found to be in perfect condition at the end of an observation period of 7 months, whereas the same lacquer without malic acid was found to have livered at the end of an observation period of 4 months.

Emm ze II Grams Drying oil modifiedglycerol--phthalateresin Zinc oxide Malio acid In 100 c. c. of xylol.

The above enamelwas found to be in perfect condition at the end of a 7 months observation period, whereas the same enamel without malic acid was found to be practically solid at the end of a 3 months observation period.

The following two examples illustrate the effectiveness of malic acid as an anti-livering agent even in cases where hydroxy acid esters are used as solvents in addition to using basic pigments such as zinc oxide.

Example III Grams Nitrocellulose Semi-drying oil modified glycerol-phthalate resin 24 Zinc oxide 40 Malic acid 1.3

composition:

Percent 30 15 10 45 The above lacquer was found to be in perfect condition at the end of an observation period of 10 months, whereas the same lacquer without malic acid was found to have agglomerated prior to Butyl lactat Butyl alcohol Ethyl alc h l Toluol Hallo acid The above lacquer was found to be in perfect condition at the end of a 6 months observation period, whereas the same lacquer without malic acid was found to have livered and agglomerated badly prior to this observation. I

It may be seen from the above two examples that malic acid is a satisfactory anti-livering agent in cases where a relatively high proportion of basic pigment and relatively low proportion of hydroxy acid ester are employed, or where a relatively low proportion of basic pigment and a relatively high proportion of a hydroxy acid ester are employed. However, in cases where both of these materials are present in high proportion the livering tendency may be so pronounced that even the reduction secured by the.

Example V Grams Non-drying oil modified glycerol-phthalate resin q 35' Zinc oxide 40 Malic acid Y 1 In c. c. of xylol.

This enamel was found to be in satisfactory condition at the end of 6 months, whereas the same enamel without malic acid was found to have become practically solid in about 6 weeks.

Example VI Grams Glycerol-phthalate resin modified with drying oil and phenol-aldehyde intermediate 35 Zinc oxi 1 40 Malie acid- 1 In 100 c. c. of xylol.

This enamel was found to be in satisfactory condition at the end of an observation period of 10 months, whereas the same enamel without malic acid was found to have livered in 10 weeks.

The following four examples illustrate suitable forms of lacquers and straight synthetic resin varnishes, both white and tinted, formulated for 5 spray application.

Example VII 1 Grams Nitrocellulose 5 55 Glycerol-phthalate resin 15 Zinc oxide '9 Malic acid 0.7

In 100 c. c. of the following solvent mixture: 60

Percent Ethyl alcohol 4 Ethyl acetate I 8 Butyl alcohol 8 Butyl acetate 30' 65 xylol 15 Toluol 35 Example VIII Grams 7 Nitrocellulose 5 Drying oil modified glycerol phthalate realm 15 Zinc oxide 7 .5. Prussian blue 3 Malic acid 0.7 In 100 c. c. of the following solvent mixture:

a Percent Xylol k 50 Petroleum naphtha... 40 Butyl alcohol 10 Example X I Grams Drying oil'modified glycerol-phthalate resin- 31.5 Zinc oxide 9 Prussian blue 4.5 lVIalic acid 0.5 In 100 c. c. of the following solvent mixture:

, r Percent Xylol 50 Petroleum naphtha 40 Butyl alcohol 10 In 100 c. c. of the following solvent mixture:

Drying oil modified glycerol-phthalate resin. 31.5 Zinc oxide 13.5

While the exact mechanism whereby malic acid reduces the tendency to liver in coating materials such as those illustrated above is not known,'it is probable that rather than entering into a chemical reaction it merely prevents the reaction product of'the basic pigment and acidic radicals in the resin from assuming the physical state of a gell or" oilarge agglomerates. .This theory is substantiated in part by the -IaCt' that V other acids suchas tartaric, succinicidumaric, -benzoic, and phthalic'iail towiaccomplish this purpose. It is to be understood, however, that my invention is not to be construed as limited to any particular theory by which it may operate.

It is to be further understood that while my invention is substantially described by the above disclosure and examples, it is not to be construed as limited to the use of the materials or combinations specifically named. Although zincoxide was the only basic pigment specified in the examples, the invention is. equally applicable to coating materials containing any other basic pigment, such as, for example, certain grades of lithopone which have an alkaline reaction. Likewise, any oi the usual types of modified polybasic acid-polyhydric alcohol resins may vided they are known to be suitable for coating materials aside from their iivering tendencies.

- desired manner, as long as above. In general, it

" scope of my invention.

or agglomerate in coating materials containing a of a character and in be used, pro- It should be noted, of course, that certain of these However, it will be found that malic acid will im- 5 prove any coating material of this type to some extent and will improve most of these coating materials sufllciently to allow for normal shelf life. .The coating materials may be modified in any they comply with the specifications with regard to iivering disclosed may be said that any modificationsor the use of, any equivalents which would naturally occur to those skilled in the art may be employed without departing from the My invention now havingbeen described, what I claim is:

1. A method or reducing the tendency to liver basic pigment and a film forming agent compris ing modified polyhydric acid-polybasic acid resin of a character and in an amount to cause a pronounced tendency to gell. or liver, which comprises adding malic acid to said coating materials.

2. A method for reducing the tendency to liver or agglomerate in coating materials containing a basic pigment and a film forming agent comprising drying oil m fied polyhydrlc alcoholpolybasic acid resin of a character and in an amount to cause a pronounced tendency to gell or liver, which comprises adding malic acid to said coating materials.

3. A method for reducing the tendency to liver or agglomerate in coating'materials containing zinc oxide and a film forming agent comprising modified glycerol-phthalate resin of a character and in an amount to cause' a pronounced tendency to gell or liver, which comprises adding 0.25% to 2.0% of malic acid to said coating ma- 40 terials. I

4. A coating compositionhaving reduced tendency to liver or agglomerate, which comprises a basic pigment, a film forming agent comprising modified polyhydric alcohol-polybasic acid resin an amount to cause a pronounced tendency to 'geli or live and malic acid.

5. A coating composition having a reduced tendency to liver or agglomer'ate, which comprises a basic pigment, a film forming agent comprising drying oil modified polyhydric alcohol-poly-basic acid resin or a character and in an amount to cause a pronounced tendency to gell or liver, and malic acid. I

6. A coating composition having a. reduced tendency to liver or agglomerate, which comprises zinc oxide, a film forming agent comprising modified glycerol phthalate resin of a character and in an amount to cause a pronounced tendency to gell or liver, and 0.25% to 2.0% of malic acid.

4 CHARLES BOGIN. 

